Examples of pertinent patents which were found are:
U.S. Pat. No. 4,039,096 PA1 U.S. Pat. No. 3,495,729 PA1 U.S. Pat. No. 3,193,124 PA1 U.S. Pat. No. 3,452,893 PA1 U.S. Pat. No. 2,395,173 PA1 U.S. Pat. No. 4,084,736 PA1 French Pat. No. 993,581
U.S. Pat. No. 4,039,096 shows a wheel chair storage apparatus. A wheel chair sits on a ramp which is lowered to the ground from a position above the top of the car. The wheel chair is stored in a casing attached to the top of the car roof by a motor which pulls the wheel chair into the casing after it has been raised above the ground.
U.S. Pat. No. 3,495,729 shows a slidable boat loader. A horizontally movable frame pivots to allow the boat to be angularly related to the top of the car roof. Two arms connected to the frame are pivotable so that the boat pivots off the now angled horizontally slidable frame onto the ground for unloading.
U.S. Pat. No. 3,193,124 shows a loading apparatus having horizontally slidable tracks having a horizontal locking device. FIG. 7 shows a spring latch which locks the horizontally slidable frame into place to prevent further horizontal movement. No vertical movement is shown. When the horizontally slidable frame reaches maximum extension a metal finger mechanically locks the horizontally slidable tracks to prevent further horizontal movement and the frame pivots, so that when an end of the frame reaches the ground further pivoting movement is restricted and the load can be removed from the frame.
U.S. Pat. No. 3,452,893 shows a roof rack having horizontally extendable tracks upon which a rollered dolly carries the cargo. The rollered dolly moves along the tracks from a position of the ground adjacent the car to a fixed position on top of the vehicle.
U.S. Pat. No. 2,395,173 shows a loading apparatus having two skid rails hingedly attached to the horizontal roof tracks for permitting the cargo to slide off the roof of the vehicle.
U.S. Pat. No. 4,084,736 shows a motorcycle rack which vertically raises the motorcycle to a fixed and locked position off the ground so that the motorcycle can be transported.
French Pat. No. 993,581 shows a roof rack having pivotable arms.
No patents show the ignition travel lock electrical interlock system which prevents the engine from starting until the travel lock of the roof rack is secured. None of the patents suggests the track locks, the carriage locks and assist rams.